Quantum electron beam probe of sidewall dry-etch damage

Damage as a result of ion bombardment may occur both at top surfaces and at sidewalls. We propose a method of probing sidewall damage using coherent electron focusing. A collimated electron beam is reflected off an internal boundary formed by dry etching. Spectra measured in an applied magnetic field are influenced strongly by increased levels of etch damage. Monte Carlo simulations combined with experiments on multiple beams reveal the separate contributions of boundary roughness and inelastic electron scattering. Electrostatic calculations reveal a damage shadow beneath the sidewall.